ESP32: A Fatal Error

September 1st, 2018

If you get this message when trying to flash an ESP32:

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

You may need to reboot it while flashing so the computer will recognize it. You should be able to trigger a reboot into flashing mode by holding down the BOOT button and giving the EN button a press. Do this while the esptool is “Connecting…”, and it should connect and write with no issues. You may need to try this several times before the tool will see it and connect.

This is what a successful flash looks like:

# make -j flash
Python requirements are satisfied.
Flashing binaries to serial port /COM4 (app at offset 0x10000 )...
esptool.py v2.5.0
Serial port C:/msys32/COM4
Connecting........_
Chip is ESP32D0WDQ6 (revision 1)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse
MAC: xx:xx:xx:xx:xx:xx
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Auto-detected Flash size: 4MB
Flash params set to 0x0220
Compressed 21184 bytes to 12571...
Wrote 21184 bytes (12571 compressed) at 0x00001000 in 1.1 seconds (effective 151.3 kbit/s)...
Hash of data verified.
Compressed 138336 bytes to 68372...
Wrote 138336 bytes (68372 compressed) at 0x00010000 in 6.1 seconds (effective 181.4 kbit/s)...
Hash of data verified.
Compressed 3072 bytes to 103...
Wrote 3072 bytes (103 compressed) at 0x00008000 in 0.0 seconds (effective 1068.5 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...

Codility And Candiate Testing: Still Sucks

September 15th, 2016

Previously: Codility And Candiate Testing

I recently applied to another position which involved Codility testing. This time around, the questions were some sort of array split, a binary positive to negative number flip, and a knight position move algorithm.

Since my last write-up, Codility has made some good improvements to their UI. The code editor is much better than it was.

The rest of my beef still remains though.

Codility is not a good measure of a programmer, and it’s a great way to filter out good candidates such as myself. (I have 15 years using PHP. Hire me? )

99% of the work I do doesn’t involve anything even close to an algorithm, so the only reason for me to learn them would be to pass screening tests. That doesn’t really seem like something useful, does it?

Fun With Automated GIF Generation

October 29th, 2013

Trolling around on the web, found a fun little process for generating animated GIFs: http://rarlindseysmash.com/posts/stupid-programmer-tricks-and-star-wars-gifs

If your IDE opens slowly …

September 20th, 2013

… remember that some programs have a list of recently opened files. And that some of those programs try to resolve the path to each of those files. And if the path to some of those files is on a network share, and said network share doesn’t exist sometimes, then your IDE will be very slow. So, clear the recently opened files list.

Codility And Candiate Testing

July 28th, 2013

Tonight, I tested through a series of tests on Codility. Well … kind of.

Codility, for those of you who haven’t heard, is a automated test tool used to filter interview candidates, or for developers to show off their chops. A great idea in practice, what this leads to in reality is testing that is geared to math, because it’s easy to evaluate automatically.

Case in point, the tests I was presented with were:

  • Movement/path overlap detection
  • Rectilinear space intersection/area calculation
  • Binary period location (P [P ≤ Q / 2] and [S[K] = S[K+P] for 0 ≤ K < Q − P])

Of these three questions, I managed to complete one and started trying to understand the other two before I said “Screw this”.

No, you didn’t read that wrong. I had a 33% success rate, and then I just didn’t care enough to keep going. I didn’t consider the problems relevant enough to my ability to bother taking them. I would not consider myself a poor programmer (in fact, a few colleagues have told me the opposite). I have been programming for over ten years, and have developed some really complex projects. I am highly creative, analytical and a good problem solver.

Maybe I’m just cranky because I didn’t complete their testing, but I would not use Codility if I ever needed to hire. Many self-taught developers are in the same boat as I am (lacking the comp-sci math background), but end up being stuck without the luxury of bailing out on the testing, because they need to test for some job they’ve applied for.

Reddit hiring is a much more useful test of ability and problem-solving.
http://blog.reddit.com/search/label/hiring

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